Sonia Gandhi, in a rare speech, exhorted the Parliament to make history by passing the Bill.
The Lok Sabha has begun voting on amendments proposed to the government's flagship Food Security Bill and will soon vote on the crucial legislation.
The six-hour debate that preceded the vote saw Sonia Gandhi make a rare speech to say, "The question is not whether we can do it or not. We have to do it."
In its reply to the discussion, the government accepted that the "food bill is not perfect" but promised to "plug loopholes along the way." Food Minister KV Thomas also sought to address a major concern of key ally Mulayam Singh Yadav and others saying, "We will protect the federal system."
Mr Yadav had said during the debate that the Bill should not be passed without calling a meeting of all chief ministers.
Determined to get its bill passed in the lower House today, the government has won crucial support for its bill by agreeing to changes broadly acceptable to the opposition as well as allies.
BSP chief Mayawati and the Janata Dal-United have said they will support the Bill, with amendments. The changes the government has made also takes into account some sought by parties like the Trinamool Congress and the Akali Dal.
Mrs Gandhi called it a chance for India to make history and described the Food Security Bill, which she has championed, as an integral part of "an empowerment revolution."
The Congress president countered opposition to the bill with a simple argument - there are hungry children and "poor brothers and sisters" and they must have a "legal right to food."
"Why didn't you bring this Bill earlier when poor people were dying of hunger? Is this for elections or for the hungry?" Mulayam Singh Yadav asked.
The BJP's Murli Manohar Joshi said, "It's not food security, but a vote securing Bill."
The Food Bill aims to provide cheap food to nearly 70 per cent of India's population at the cost of Rs 1.25 lakh crores, and is the Congress's main lifeline as it tries to win a third straight term in next year's elections.
To ensure that the Bill was debated today, the government had to promise that Prime Minister Manmohan Singh will "intervene" in a discussion on missing coal files.